The present invention concerns a joint, for instance a universal joint, joining a transmission drive member and a gear-shifting system of a transmission.
In automobiles using a manual transmission, the transmission generally is either directly or indirectly integrated into the engine, or, in the case of a so-called transaxle design, is mounted apart from the engine on the motor vehicle body. In the former case, operation of the engine inevitably results in vertical or sideways vibrations, which are propagated through the transmission and the gear-shifting system to the shifting lever mounted inside the car unless there is sufficient decoupling of the vibration-susceptible parts. However, even when such decoupling is provided, vibrations arising in normal driving, particularly, vibrations generated by the torque transfer in the transmission, may nonetheless propagate acoustically on the gear-shifting lever to the vehicle inside unless adequate decoupling between the vibratory systems is assured.
An appropriate remote-controlled joint between a transmission and its gear-shifting mechanism is disclosed in German patent 41 00 574, the joint being intended for the so-called transaxle design.
However this known design has a number of drawbacks. The design is complex and hence costly, which is particularly disadvantageous when the design is incorporated into an automobile mass production line. Typically, this joint comprises two joint parts frictionally locked to each other through a complex coupling device. The device includes a coupling for transmitting the force. The coupling is held in place within a joint part by a joint pin. Mounted between the coupling and the joint pin is a tubular, elastically deforming body. Upon actuation of the gear-shift lever inside the car, the tubular body deforms and assures soft meshing of the two joint parts. Once the body is elastically deformed, frictional locking takes place when the rigid coupling engages rigid stop rings.
However, during the deformation of the elastic, tubular body, a relative motion takes place between the rigid coupling and the rigid stop rings. Intrinsically, the contact between these rigid elements will enhance the propagation of undesired vibrations. Furthermore, the relative motion between these rigid elements will result in abrasion and hence wear-causing friction.
It is thus seen that the prior art joint cannot reliably suppress the undesired propagation of vibration over an extended time of use between the vehicle transmission and the inside of this vehicle. Furthermore, because of the relative motion between rigid elements resulting in wear, the prior art joint is more susceptible to malfunction and is more expensive because of the number of components used.
Accordingly it is the object of the present invention to eliminate the cited drawbacks by creating a joint, such as a universal joint, between a transmission drive member and the gear-shifting system of a transmission which provides excellent driving comfort and is characterized by long service life and also by reliable gear-shifting.